title: Messenger RNA expression patterns of p75 neurotrophin receptor and tropomyosin-receptor-kinase A following spinal cord injury.
abstract: BACKGROUND
  Induction of p75 neurotrophin receptor (p75NTR) could be one of the first steps that initiate apoptotic cascade after injury, or it may indicate regeneration responses undertaken by the injured system, possibly in collaboration with resident tropomyosin-receptor-kinase (Trk).
  
  
  OBJECTIVE
  To measure quantitative changes in messenger RNA (mRNA) expression levels of p75NTR, Trk A, and caspase-9 in rat's injured spinal cord (SCI). The reciprocal interaction between Trk and p75NTR signaling pathways can dictate cellular responses to neurotrophins. p75NTR can regulate Trk-dependent responses, but the role of Trk in regulating p75NTR-dependent signaling is not well documented.
  
  
  METHODS
  Using real-time polymerase chain reaction, this study analyzed changes in the mRNA abundance of the mentioned genes at 6, 24, and 72 hours and 7 and 10 days after SCI in adult male rats. SCI was induced at T9 level by transsection.
  
  
  RESULTS
  Results show a complicated temporal and spatial pattern of alteration with different degrees and direction (up- or down-regulation) in p75NTR, Trk A, and caspase-9 mRNA expression levels after SCI. The greatest variation was seen in center regions following SCI. This study shows that alteration in p75NTR, Trk A, and caspase-9 expression starts as early as 6 hours after SCI. Alterations in p75NTR, Trk A, and caspase-9 expression within the spinal cord may play a key role in the apoptotic cell death.
  
  
  CONCLUSIONS
  Results suggest that the role of p75NTR is to eliminate damaged cells by activating the apoptotic machinery, especially at the center of damage and during first week after injury.
authors.affiliation: Cell and Molecular Biology Division, Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Montazeri
authors.forename: Abolghasem
authors.initials: A
authors.lastname: Esmaeili
authors.forename: Mehran
authors.initials: M
authors.lastname: Miroliaei
authors.forename: Sayed Jamal
authors.initials: SJ
authors.lastname: Moshtaghian
mesh_terms: D000818:Animals; D053453:Caspase 9 / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D004195:Disease Models, Animal; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D020800:Receptor, Nerve Growth Factor / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D020917:Receptor, trkA / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013119:Spinal Cord Injuries / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D012333:RNA, Messenger; D020800:Receptor, Nerve Growth Factor; D020917:Receptor, trkA; D053453:Caspase 9